Writing for The Huffington Post, Mr McCluskey, whose union is Labour’s biggest financial backer, claimed that he was “at a loss to understand the motives” of Jewish leaders, adding that they had “simply refused to take ‘yes’ for an answer”.

He named the Board of Deputies, the Jewish Leadership Council and the Jewish Labour Movement as he said that when Mr Corbyn had attempted to “build bridges” with them, they had shown “intransigent hostility and an utter refusal to engage in dialogue about building on what has been done and resolving outstanding difficulties.

“I therefore appeal to the leadership of the Jewish community to abandon their truculent hostility, engage in dialogue and dial down the rhetoric, before the political estrangement between them and the Labour Party becomes entrenched.”

Corbyn apologises for Labour anti-semitism row

Whilst Mr McCluskey joined with other union leaders in calling for the adoption of the full International Holocaust Remembrance Alliance definition of anti-Semitism, he added moderate Labour MPs were trying to use the issue as “rocket fuel” to split the party.

A spokesman for the Board of Deputies said: “His attack on the Jewish community is both unfair and unwarranted. We have had a deluge of words from the Labour leadership. It is about time that the Party resolved this crisis by taking the firm and decisive action which the communal leadership set out for them in detail months ago. They have so far failed to do what is right.”

John McDonnell, the shadow chancellor, also criticised MPs considering a breakaway party, saying: “For anybody to use the issue of anti-Semitism as a cover for launching a new political party they had been planning for nearly two years would rightly be seen as an act of appalling cynicism, basely exploiting a genuine concern that people of goodwill are working hard to address.”

A YouGov poll revealed that one in eight Labour supporters and 16 per cent of all voters think worse of Mr Corbyn as a direct result of the row over his visit to the graves of Black September terrorists.

The survey found that over the past month the number of Labour voters who think he is doing “well” as leader has fallen from 53 per cent to 44 per cent, while 45 per cent think he is doing “badly”. Across the electorate as a whole, 65 per cent say he is doing badly.